A New Spectrum Sensing Scheme using Three Adaptive Thresholds Based on Energy DetectionAdvisor : Associate Professor Jaeshin Jang Ph.D.Student : Cahyo Tri SatrioDepartment of Information and Communication Engineering1Outline Introduction Energy Detection Proposed Scheme Three Adaptive Thresho!ds "ased on Energy Detection# Simu!ation $esu!t and Conc!usion 2Introduction In cognitive radio% spectrum sensing is very crucia! part of the &ho!e process in cognitive radio. Spectrum sensing &i!! a!!o& 'n!icensed 'ser Secondary 'ser# to uti!i(e !icensed spectrum )y detecting spectrum ho!es &ithout causing interferences to the *icensed 'ser Primary 'ser# . There are various techni+ues or schemes for spectrum and among them the energy detector needs !itt!e prior ,no&!edge of Primary 'ser P'# signa! than other scheme. -o&ever% the energy detection is not ro)ust especia!!y in !o& signa! to noise ratio rate S.$#% and thus the pro)a)i!ity of detection Pd# &ou!d )e very !o&.3Energy detection The conventiona! energy detection &as introduced in /01% )ut the performance of this techni+ue &as !imited )y noise uncertainty. T&o2thresho!d energy detection &as proposed in order to so!ve the pro)!em of noise uncertainty. -o&ever% there is a ne& pro)!em for these techni+ues% 3Confused $egion Pro)!em4. This pro)!em &i!! happen &hen a!! the statistic energy fa!!s )et&een upper and !o&er thresho!d /51. In /61% the authors introduce -ierarchica! Cooperative Spectrum Sensing to so!ve the confused region pro)!em% )ut this techni+ue needs a !ot of additiona! re+uirements. In the other hand% the dynamic thresho!d a!gorithm &as proposed for com)ating the noise uncertainty /71.4Three Adaptive Thresholds Based on Energy Detection In /61% the author proposed hierarchica! cooperative sensing using dou)!e thresho!ds &herein those scheme needs 8usion Center 8C# to avoid sensing fai!ure pro)!em and ma,e decision &hen the energy fa!!s )et&een the t&o thresho!ds9 this increases the system re+uirement. In order to so!ve the same pro)!em &ithout increase the re+uirement% &e propose a ne& spectrum sensing scheme &ith three adaptive thresho!d.5Three Adaptive Thresholds Based on Energy Detection Three di:erent thresho!ds are com)ined from dou)!e adaptive thresho!ds techni+ue and one adaptive thresho!d that &e put at confused region to overcome sensing fai!ure and get the )etter performance of spectrum sensing due to noise uncertainty.6;heredenote as min thresho!d anddenote ma< thresho!d/;e choose upper )ound of dou)!e thresho!d to app!ying the dynamic thresho!d factor to ma,e another thresho!d in confused region The noise uncertainty in the &ire!ess environment is descri)e as /% 1% &here as noise uncertainty and The va!ue of dynamic thresho!d can )e summari(ed as/% 1. &here as dynamic thresho!d factor and Simulation Result and Conclusion The simu!ation is imp!emented in =at!a) $5>0>)#. ;e assumed tota! num)er of samp!e .# as 0>>>%S.$ range from 26> to > d"% Pro)a)i!ity of fa!se a!arm% ? >.0% ?0.>6% @ ?0.>A% and BPSC modu!ation is considered in A;D. channe!. 7$FC curve for energy detection &ith proposed scheme &hen primary user is presentA ne& spectrum sensing scheme using three adaptive thresho!ds )ased on energy detection &as proposed in this paper. "ased on simu!ation resu!t our scheme gives more improvement for sensing performance and gives )etter performance than t&o conventiona! schemes &ithout increased computing comp!e